Re: fattr4_hidden and fattr4_system r/w attributes in Linux NFSD?

Re: fattr4_hidden and fattr4_system r/w attributes in Linux NFSD?

[Sebastian Feld]

On Mon, Apr 28, 2025 at 4:15 PM Chuck Lever <chuck.lever@oracle.com> wrote:
>
> Hi Sebastian -
>
> On 4/28/25 7:06 AM, Sebastian Feld wrote:
> > I've been debating with Opentext support about their Windows NFS4.0
> > client about a problem that the Windows attributes HIDDEN and SYSTEM
> > work with a Solaris NFSD, but not with a Linux NFSD.
> >
> > Their support said it's a known bug in LInux NFSD that "fattr4_hidden
> > and fattr4_system, specified in RFC 3530, are broken in Linux NFSD".
>
> RFC 7530 updates and replaces RFC 3530.
>
> Section 5.7 lists "hidden" and "system" as RECOMMENDED attributes,
> meaning that NFSv4 servers are not required to implement them.
>
> So that tells me that both the Solaris NFS server and the Linux NFS
> server are spec compliant in this regard. This is NOTABUG, but rather it
> is a server implementation choice that is permitted by RFC.
>
> It is more correct to say that the Linux NFS server does not currently
> implement either of these attributes. The reason is that native Linux
> file systems do not support these attributes, and I believe that neither
> does the Linux VFS. So there is nowhere to store these, and no way to
> access them in filesystems (such as the Linux port of NTFS) that do
> implement them.
>
> We want to have a facility that can be used by native applications
> (such as Wine), Samba, and NFSD. So implementing side-car storage
> for such attributes that only NFSD can see and use is not really
> desirable.

I did a bit of digging, that debate started in 2002.

23 years later, nothing happened. No Solution.
Very depressing.

Sebi
-- 
Sebastian Feld - IT security consultant

Re: fattr4_hidden and fattr4_system r/w attributes in Linux NFSD?

[Chuck Lever]

On 4/29/25 9:10 AM, Sebastian Feld wrote:
> On Mon, Apr 28, 2025 at 4:15 PM Chuck Lever <chuck.lever@oracle.com> wrote:
>>
>> Hi Sebastian -
>>
>> On 4/28/25 7:06 AM, Sebastian Feld wrote:
>>> I've been debating with Opentext support about their Windows NFS4.0
>>> client about a problem that the Windows attributes HIDDEN and SYSTEM
>>> work with a Solaris NFSD, but not with a Linux NFSD.
>>>
>>> Their support said it's a known bug in LInux NFSD that "fattr4_hidden
>>> and fattr4_system, specified in RFC 3530, are broken in Linux NFSD".
>>
>> RFC 7530 updates and replaces RFC 3530.
>>
>> Section 5.7 lists "hidden" and "system" as RECOMMENDED attributes,
>> meaning that NFSv4 servers are not required to implement them.
>>
>> So that tells me that both the Solaris NFS server and the Linux NFS
>> server are spec compliant in this regard. This is NOTABUG, but rather it
>> is a server implementation choice that is permitted by RFC.
>>
>> It is more correct to say that the Linux NFS server does not currently
>> implement either of these attributes. The reason is that native Linux
>> file systems do not support these attributes, and I believe that neither
>> does the Linux VFS. So there is nowhere to store these, and no way to
>> access them in filesystems (such as the Linux port of NTFS) that do
>> implement them.
>>
>> We want to have a facility that can be used by native applications
>> (such as Wine), Samba, and NFSD. So implementing side-car storage
>> for such attributes that only NFSD can see and use is not really
>> desirable.
> 
> I did a bit of digging, that debate started in 2002.
> 
> 23 years later, nothing happened. No Solution.
> Very depressing.

It's a hard problem.

Focus on the recent work. It appears to be promising and there have
been few objections to it.


-- 
Chuck Lever

Re: fattr4_hidden and fattr4_system r/w attributes in Linux NFSD?

[Sebastian Feld]

On Tue, Apr 29, 2025 at 3:45 PM Chuck Lever <chuck.lever@oracle.com> wrote:
>
> On 4/29/25 9:10 AM, Sebastian Feld wrote:
> > On Mon, Apr 28, 2025 at 4:15 PM Chuck Lever <chuck.lever@oracle.com> wrote:
> >>
> >> Hi Sebastian -
> >>
> >> On 4/28/25 7:06 AM, Sebastian Feld wrote:
> >>> I've been debating with Opentext support about their Windows NFS4.0
> >>> client about a problem that the Windows attributes HIDDEN and SYSTEM
> >>> work with a Solaris NFSD, but not with a Linux NFSD.
> >>>
> >>> Their support said it's a known bug in LInux NFSD that "fattr4_hidden
> >>> and fattr4_system, specified in RFC 3530, are broken in Linux NFSD".
> >>
> >> RFC 7530 updates and replaces RFC 3530.
> >>
> >> Section 5.7 lists "hidden" and "system" as RECOMMENDED attributes,
> >> meaning that NFSv4 servers are not required to implement them.
> >>
> >> So that tells me that both the Solaris NFS server and the Linux NFS
> >> server are spec compliant in this regard. This is NOTABUG, but rather it
> >> is a server implementation choice that is permitted by RFC.
> >>
> >> It is more correct to say that the Linux NFS server does not currently
> >> implement either of these attributes. The reason is that native Linux
> >> file systems do not support these attributes, and I believe that neither
> >> does the Linux VFS. So there is nowhere to store these, and no way to
> >> access them in filesystems (such as the Linux port of NTFS) that do
> >> implement them.
> >>
> >> We want to have a facility that can be used by native applications
> >> (such as Wine), Samba, and NFSD. So implementing side-car storage
> >> for such attributes that only NFSD can see and use is not really
> >> desirable.
> >
> > I did a bit of digging, that debate started in 2002.
> >
> > 23 years later, nothing happened. No Solution.
> > Very depressing.
>
> It's a hard problem.
>
> Focus on the recent work. It appears to be promising and there have
> been few objections to it.

Do you have any reference to that work? Are there status updates?

Sebi
-- 
Sebastian Feld - IT security consultant